The present invention relates to an operation switch having an operation surface area with a specified pattern printed thereon and, more particularly, to a soft-feeling operation switch allowing a user to operate it feeling a pleasant soft touch.
Japanese Utility Model Publication No. 2597852 discloses a conventional switch developed as a membrane switch being a soft-touch key used for a telephone dial button, which has a plastic film substrate surface with a pattern printed thereon and covered with a transparent paint coat being soft to the touch.
However, this type of operation switches having a pattern-printed surface with a coat of soft-feeling paint to be soft to the touch may have such a disadvantage that repeated finger-pressure operations may cause the coat layer to become loose and separated from the pattern-printed layer because the latter layer formed by a printing ink material contains silicone as an anti-cracking agent thereby reducing the adhesion of the coat layer thereto. In other words, the switch may have the decreased durability of the soft-feeling coat against the repeated finger-pressure operations.
To prevent the separation of the coated layer from the pattern-printed surface, there has been developed a switch having a surface with a specified pattern printed by laser etching and covered with a soft-feeling coat of paint.
As described above, the common problem of the conventional soft-feeling switches of the type having a pattern-printed surface with a soft-feeling coat formed thereon is low durability of their soft-feeling coat that may become loose and peel off by repeatedly pressing it by the user""s finger during the operation period because of insufficient adhesion between the pattern-printed surface and the soft-feeling coat of paint.
On the other hand, drawbacks of the conventional switch having a specified pattern printed by laser etching on its operation surface and then covered with a soft-feeling paint coat is that it is expensive to manufacture by using a laser etching equipment and may be of larger unevenness of its surface in comparison with a switch having a surface first coated with a soft-feeling paint and then pattern-printed thereon.
Accordingly, an object of the present invention is to provide an operation switch having an operation surface with a specified pattern printed thereon, which is capable of withstand repeated finger-touch operations for a long service time without loosening and separating a soft-feeling layer (a coat of soft paint) from the pattern-printed surface of its substrate (base material) owing to the high strength and durability of the interlayer adhesion achieved by first printing the specified pattern on the substrate by using a siliconeless printing ink (i.e. a printing ink without silicone as an ingredient) and then applying thereon a soft-feeling coat of a transparent or semitransparent soft-painting material.
Another object of the present invention is to provide an operation switch having an operation surface with a specified pattern printed thereon, which is capable of withstand repeated finger-touch operations for a long service time without loosening and separating the pattern-printed layer from a soft-feeling layer (a coat of soft paint) of its substrate (baste material) owing to the high strength and durability of the interlayer adhesion achieved by first covering the substrate surface with a soft-feeling layer of soft painting material and then printing thereon the specified pattern by using a siliconeless printing ink.
Another object of the present invention is to provide an operation switch having an operation surface with a specified pattern printed thereon, which is capable of withstand repeated finger-touch operations for a long service time without loosening and separating a soft-feeling layer from the pattern-printed surface of its substrate owing to the high strength and durability of the interlayer adhesion achieved by first covering the substrate surface with a soft-feeling layer of a transparent or semitransparent soft painting material and then printing thereon the specified pattern by using a two-component isocyanate setting type urethane ink.
Another object of the present invention is to provide an operation switch having an operation surface with a specified pattern printed thereon, which is capable of withstand repeated finger-touch operations for a long service time without loosening and separating the pattern-printed layer from a soft-feeling layer (a coat of soft paint) of its substrate (base material) owing to the high strength and durability of the interlayer adhesion achieved by first covering the substrate surface with a soft-feeling layer of soft painting material and then printing thereon the specified pattern by using a two-component isocyanate setting type urethane ink ink.